System for selective radio reception



Aug. 25, 1936. D. 1.. GRUBB 2,051,845

SYSTEM FOR SELECTIVE RADIO RECEPTION Filed Dec. 9, 1952 2 Sheets-Sheet 1Rec 9/ Wu Set INVENTOR 93.91 143:. rimzwb Aug. 25, 1936. D. 1.. GRUBB2,051,345

SYSTEM FOR SELECTIVE RADIO RECEPTION Patented Aug. 25, 1936 UNITEDSTATES PATENT OFFICE SYSTEM FOR SELECTIVE RADIO RECEPTION 13 Claims.

My invention relates to tuning systems and particularly to predeterminedmechanical selective tuning systems for radio receiving sets.

The object of my invention generally stated, is the provision of atuning system that is simple in operation and readily installed inexisting radio sets.

A more specific object of my invention is to provide for theestablishment of the reception of specific broadcasting stations at aspecific hour of the day without hand manipulation of ordinary tuningdials.

Another object of my invention is to provide simple and illustrativepanels arranged to receive contact plugs or pins which when inserted ina panel represents the predetermined time of reception of thebroadcasting station which that panel represents.

Another object of my invention is to provide a contact arrangement thatwill discontinue reception during the time that the system isinoperative.

Other objects of the invention will, in part, be obvious and will, inpart, appear hereinafter.

The accompanying drawings which disclose my invention show themechanical elements in elevation, some parts of which are in section andbroken away and the electrical system diagrammatically arranged. Fig. 1represents the system in connection with some of the mechanical parts.Fig. 2 represents a portion of the system in conjunction with theplurality of mechanical parts not illustrated in Fig. l, and one methodof connecting the mechanical system to the radio tuning devicescontained in an ordinary radio receiving set. Fig. 3 is a side elevationof a contact disc. Fig. 4 is a side elevation of one of the cams in myinvention. Fig. 5 is a side elevation of another cam. Fig. 6 is asection on the line 66 on Fig. 1.

Referring to 1, A and B represent the source of electrical energy forsupplying the system. Current travels from the source A through theconductors l and 2 to the coil 3 of the radio set control magnet 4.

When the magnet 4 becomes energized it attracts the armature 5 againstthe tension of the spring 6, opening the contacts 1 and 8 anddisconnecting the supply circuit for the radio receiving set.

The armature 5 is pivoted at one end 9. The pendent lug I on the otherend of the armature is arranged to mechanically engage the armature llof the magnet l2 which is pivoted intermediate of its ends at l3. Thespring 14 holds one end of the armature ll against the pendent memberif! of the armature 5, the other end of the armature being in positionto be attracted by the magnet 12 when its coil I5 is energized.

After the coil 3 of the magnet 4 has been en- 5 ergized and the armature5 has been picked up, the pendent lug ID will release the armature llcausing it to strike the pin IS in which position it will stay until thecoil l5 of the magnet I2 is energized and draws the armature I I to itsnormal position as shown. The magnet 4 is energized momentarily and whenthe armature 5 is released it will drop, causing the bottom surface ofthe pendent member ID to engage with the top end of the armature H andpreventing the 15 contacts I and 8 from coming into electricalengagement until the magnet I2 is energized and pulls the armature Hpast the shoulder of the pendent member.

The current flowing from the source A passes through the coil 3, theconductor I1 and the contacting member I8 when it is in contact with oneof the four contacts I9, 29, 2| and 22. The contactor I8 is rotatablymounted on a minute hand shaft of a clock or time piece which causes itto come in contact with one of the four contacts at the end of everyfifteen minute period.

I have chosen periods of fifteen minutes in length because broadcastingstations use that as the shortest period for their programs. Such methodof timing is well known in several arts and its application hasdeveloped many flexible timing devices, most of which could be used inthis invention.

The current passing through the contactor I8 to one of the four contactsI9, 20, 2| and 22, will flow through their corresponding conductors tothe contacts 23, 24, 25, and 26 mounted in the contact carrying bar 21which is made of suitable insulating material. The contacts 23, 24, 25,and 26 are in multiple with several sets of contacts (only 23, 24, 25',and 26 being additionally shown), each set of which represents one hourperiod of fifteen minute intervals. The number of multiple sets ofcontacts representing the total continuous period over which the systemwill be automatically controlled may be any convenient number of hoursof a day.

The guide rods or bars 28 and 29' have slidably mounted thereon thecarriage 30 which carries the collars 3| and 32. The latter, fittingsnugly on the bar 29, acts as sliding electrical contacts for thecarriage 30. The bar 28 contains notches or steps 33 on the side facingthe bar 29, which steps are equally spaced, being of the same height asthe distance between the contacts on the bar 21. v The contactor 34 ismounted on a suitable insulated block on one end of the carriage so asto engage each of the contacts in the contacting strip 21 at successiveintervals as the carriage descends step by step down the bars 28 and 29.

The carriage 30 is provided with a recess 35 to admit the slidingarmature 36 which is held in place by a suitable means such as the plate31. The end 38 of the armature acts as a pawl or detent for engaging theupper faces of the steps 33. The other end of the armature is providedwith an armature lug 39 which is arranged to be acted upon by themagnetic flux of the magnet coil 40. A spring 4| is held in compressionbetween the body of the carriage and the armature, forcing the latteraway frornthe coil 40 and the detent 38 into a groove forming one of thesteps 33.

The current flowing from A through the rotating contactor l8, thecontacts l9 and 25, the sliding contactor 34 to the coil 40 returnsthrough the sliding contact between the carriage 30 and the guide bar 29to the conductor 41 and the return circuit B. The coil of the magnet 46being energized attracts the armature 36 which compresses the spring 4|and withdraws the armature pawl 38 from the step 33 on which it rests,releasing the carriage and opening the circuit connection between thecontactor 34 and the contact 25 which deenergizes the magnet 40,releasing the armature 36 and allowing the pawl 38 to engage in the nextlower consecutive step 33. The sliding contactor 34 is then inengagement with the contact 26.

The horizontal selector contactor 42 is pivotally mounted on the end ofthe carriage and is held in its mid or horizontal position by twosprings 42 and 42" opposing each other. The contactor 42 momentarilyengages certain contact pins 43 as the carriage descends from one step33 to the next lower step. The contact pins 43 are removably mounted inthe switchboard 44 which is a plurality of vertical metallic panels 45,as shown in Fig. 2 insulated from each other or spaced apart, eachrepresenting one of several broadcasting stations. Each panel contains avertical series of holes 46 which are equally spaced from each other thesame distance the steps 33 are separated from each other, successively.The contactor 42 extends the entire width of the switchboard 44 so thatit will strike an inserted pin 43 in any one of the panels as thecarriage 36 proceeds downwardly. Each of the panels. 45 forms part of anelectrical circuit. The conductors 48 electrically connect the panelsseparately to corresponding coils 49 of the selecting magnets 50, therebeing a separate coil and magnet for each station.

I will now describe the operation of my apparatus with reference to thetuning in of one station, and then explain how any of the other stationsmay be tuned in. Assume the parts are as in Figs. 1 and 2, where thecontact I9 is connected through the contacts 25 and 34 to the coil 46 ofthe magnet 56, as shown in the upper part of Fig. 1. Assume that astation corresponding to the central panel 45 in Fig. 3 is to be tunedin.

As soon as the contactor l8 engages the contact I9, current in thewinding 40 causes the armature 36 to move to the right and withdraw itsdetent 38 from the step 33 on which it rests. The carriage 30 drops, andas the current is cut off from the magnet as soon as the contactor 34leaves the contact 25, the magnet 56 is deenergized and the armature 36is forced by its spring 40 to move to the left and interlock with thenext lower step 33, which is the fourth from the top of the guide bar28. At this time the contactor is on the contact 26 which is in circuitwith the timer contact 20. However, the contactor 42 has passed thecontact pin 43 shown just below it in Figs. 1 and 2, it being assumedthat the panel 45 in Fig. 1 is the middle panel in Fig. 2. When thecarriage 30 dropped, the contactor 42 stopped just above and out ofcontact with the contact pin 43 in the right hand panel 45.

When the contactor 42 hit the contact pin 43 just below it in Figs. 1and 2, current flowed from the source A through the conductors I and 5|,the winding I5 of the magnet |2, the conductor 52, the winding 49 of themiddle magnet 50 shown in Fig. l as connected to the middle panel 45 bythe middle wire 48. From this panel, the one shown in Fig. 1, currentflows through the contacts 42 and 43 as the former passes below thelatter, and thence through the carriage 30, the guide bar 29 and theconductor 41 to the source B.

When the central magnet 56 is energized, the armature 55 thereof, whichis slidable in a slot 54 in the fixed base 53, is drawn to the left inFig. 1. The armature has on one end an arma- 7 ture lug 56 within thefield of the electromagnet 50 so that the magnet when energized willdraw the armature to the left against the tension of the spring 56. Theopposite end 50 of the armature extends into the slot 60 in the verticalsliding member and locks the same in its upper position as shown in Fig.I. The armature 55 is also provided with a slot 62 through which extendsthe upright member 63 of the selector bar 64. The member 63 has on itsupper end a lug 65 forming a shoulder which engages over its cooperatingarmature 55 and supports its cooperating selector bar, as shown in Fig.1, this bar being the central one. The free member 6| is verticallyslidable through the hole 66 in the base 53 and is limited in itsdownward movement by the shoulder 61. The contact lever 68 supported atits free end by the member 6| is pivoted between its ends at 69 and theother end has attached thereto the contact 10 which engages the contact1| when the shoulder 61 of the member 6| is forced by the spring 12attached to the lever 68, to rest on the base member 53.

The selector bar 64 is pivoted at 13 to the base 53. The contact 14mounted on one end of the selector bar is arranged to engage the contact15 fixed to the under side of the base 53. The contact 11 on the member6| is arranged to contact with the contact 16 on the selector bar, whichis immediately below the member 6|, when the pendent lug 18 on theselector bar rides on the selector drum 19 upon the release of theselector bar by the retraction of the armature 55 from beneath the lug63 on the member 6|. These contacts will open when the lug 18 drops inthe recess 80 in the middle section of the drum 19. The other end of theselector bar 64 is arranged to be mechanically lifted or reset by thecam 82 which is turned by the shaft 83 operated by the motor 84 throughthe shaft 85, the beveled gears 86 and 81, the clutch 88, the worm 89,and the worm wheel 96 which is secured to the shaft 83. The cam 82 willupon operation reset the selector bar 64 for a subsequent operationafter it has functioned.

The cam 9| shown in Figs. 2 and 4 contains the slot 92 and is made toreceive the arm 93 of the armature 94 which also operates the clutch 88.The armature 94 is operated by the magnet coil 95. The cam 9I will bringthe shaft 83 to rest after the clutch 88 is disengaged, the arm 93riding around on the cam 91 and locking the same as it engages the slot92.

The contact disc 96 shown in Figs. 2 and 3 is made of suitablenon-conductive material and has imbedded in its periphery the metallicblock 91 which is used to close the circuit between the contacts 98 and99 as the disc revolves with the shaft 83.

The selector drum 19 is divided transversely into sections as shown inFig. 2. Each section is adjustable about the shaft I02 by means of theset screws I25 and cooperates with its supplementary selector magnet 50and selector bar 64, the magnets being electrically controlled throughtheir individual panels 45 which represent different broadcastingstations.

The shaft I02 operates the tuning devices of the radio receiving set asis indicated by the variable condenser I09 of Fig. 2. The shaft I02 hasattached thereto the gear 103 meshed with the worm gear I04 that isfixed to the shaft I95. The magnet coil I06 is arranged, as is to bepresently explained, to operate the clutch I01 through the leverarmature I08 that is held in its unenergized position by the spring I09.

The operation of the selector circuit is as follows: As the carriage 30descends to the next consecutive step 33 the contactor 42 closesmomentarily the circuit through the selector magnet 49 and the radiocontrol reset magnet I5. When the selector magnet 49 becomes energizedit draws the armature 55 to the left and releases the upright member 63,permitting the selector bar 64 to drop. The selector pendent lug 18 thensupports the bar by resting on the drum. The armature 55 also unlocksand releases the member 6I which drops and closes the contacts 10, IIand 16, 11.

The former contacts close the circuit of the motor whose direction ofrotation is selected by reversing switch I I0 operated by the pins I I Iand H2 on the drum 19. From the source A the motor circuit is throughthe conductor I, the motor 84, the conductor I I3 or the conductor I I4,the conductor II5, the contacts 10 and 1! to the conductor 41 and thereturn circuit B. The contacts 16, 11 close the circuit for operatingthe clutch I01 by allowing the current to flow from A through theconductors I and H6, the coil I 06, the conductor I I1, the contacts 98,91, and 99, the conductor H8, the contacts 16, 11, and the conductors II9 and 41 to the return circuit B. When the magnet I06 becomes energizedit closes the clutch I01, thereby allowing the motor to drive theselector drum 19.

As the drum revolves the selector lug 18 on the middle bar 64 ridesthereon until it engages in the recess in the middle section of thedrum, whereupon the circuit of the magnet coil I06 is opened by theparting of the contacts 16 and 11 and the clutch I01 opens. The contacts16 and 11 are still prevented from closing because the member 6| is heldfrom dropping by the lug 61. The radio broadcasting station has now beenselected and the drum is locked in the selected position.

When the lug 18 of the selector dropped into engagement with the slot 80provided therefor, the contacts 14 and 15 closed and completed a circuitfor controlling the selector bar resetting mechanism. Tracing thecircuit, the current flows from A through the conductors I and I20, thecoil 95, the conductor I2 I, the contacts 14, 15, and the conductor 41to the return circuit 13. The magnet coil 95 is energized by current inthis circuit.

The magnet 95 operates the clutch 88 causing the motor to drive theshaft 83. The attraction of the armature 94 by the coil 95 disengagesthe locking member 93 from the recess or slot 92 in the cam 9I, freeingthe shaft 83 for rotation. As the shaft 83 revolves, the locking member93 is held away from the cam SI and the cam 82 lifts the selector bar toits normal position as shown on the drawing. As the selector bar isbeing raised, the contacts 14 and 15 open the circuit through the clutchcoil 95 and release the armature 94. The locking member 93 of thearmature 94 then rests upon the periphery of q the cam SI maintainingthe clutch 88 in partial engagement and allowing the motor to continueto drive the shaft 83. As the selector bar continues to rise by theaction of the cam 82, the I member 6| operates the lever 68 and opensthe contacts 19 and H in the motor circuit. The momentum of the rotor inthe motor is sufficient to drive the resetting cam 82 back to its normalposition where it is locked by the locking member 93 engaging the slot92 of the cam 9|, and at this time the clutch 80 becomes fullydisengaged.

The apparatus is now reset for a subsequent selection that will occur atthe end of the next fifteen minute period and the selection will begoverned according to the positioning of the contact pins 43.

In order to prevent the clutch 101 from being engaged when the selectorbars are being reset,

the contactor disc is arranged to keep the circuit through the magnetI06 open when the shaft 83 is rotating.

Nothing has been said about the resetting of the carriage 30 after thetotal period of its descent. It is evident that it could be reset byhand, a lever or a motor.

Although I have described the operation so far with reference to only asingle station which is controlled by current through the middle panel45, the middle conductor 48, the middle magnet 50, the middle selectorbar 64, and the middle section of the drum 19, it will be readilyunderstood that the tuning in of any of the other four stations will beefiected in the same manner only a panel 45 corresponding to a selectedstation will have a pin 43 placed in the proper hole 46 to be engaged bythe contactor 42 upon its release at the proper time. If the right handpanel is selected, the contactor 42 will at the proper time engage thepin 43 in that panel, causing current to flow through the right handpanel, the right hand conductor 48, and the coil of the right handmagnet 50. The armature of this magnet would then release the right handselector bar 64 which would drop upon the right hand by the contactor, aselector contactor arranged for step by step movement, a series ofsteps, releasable means for holding the contactor at each step, meanscontrolled by current through the movable contactor and any of. the saidcontacts for releasing the releasable means to permit the selectorcontactor to move to the next step, a switchboard containing a series ofpanels, one for each station, contact pins operatively positioned inselected panels and directly engaging the selector contactor at apredetermined time, tuning means for the said stations, and meanscontrolled by current through each pin when engaged by the selectorcontactor for moving the tuning means to bring in the stationcorresponding to the pin so engaged.

2. In a station selector for radio receivers, a time piece with acontactor having constant speed, contacts arranged to be engagedserially by the contactor, a selector contactor arranged for step bystep movement, a series of steps, an armature for holding and releasingthe contactor at each step, an electromagnet controlled by currentthrough the movable contactor and any of the said contacts for releasingthe releasable means to permit the selector contactor to move to thenext step, a switchboard containing a series of panels, one for eachstation, contact pins operatively positioned in selected panels anddirectly engaging the selector contactor at a predetermined time, avariable tuning condenser for selecting the stations in a radioreceiver, and a plurality of. electromagnets controlled by currentthrough their corresponding panels and each pin inserted therein whenengaged by the selector contactor for controlling the movement of thevariable condenser to tune in the station corresponding to the pin soengaged.

3. In a station selector for radio receivers, a time piece with acontactor having constant speed, contacts arranged to be engagedserially by the contactor, a selector contactor arranged for step bystep movement, a series of steps, an armature for holding and releasingthe contactor at each step, an electromagnet controlled by currentthrough the movable contactor and any of the said contacts for releasingthe releasable means to permit the selector contactor to move to thenext step, a switchboard containing a series of panels, one for eachstation, contact pins operatively positioned in selected panels anddirectly engaging the selector contactor at a predetermined time, avariable tuning condenser for selecting the stations in a radioreceiver, and a plurality of armatures controlled by current througheach pin when engaged by the selector contactor for controlling themovement of the variable condenser to bring in the station correspondingto the pin so engaged 4. In a station selector for radio receivers, atime piece with a contactor having constant speed, contacts arranged tobe engaged serially by the contactor, a selector contactor arranged forstep by step movement, a series of steps, an armature for holding andreleasing the contactor at each step, an electromagnet controlled bycurrent through the movable contactor and any of the said contacts forreleasing the holding means to permit the selector contactor to move tothe next step, a switchboard containing a series of panels, one for eachstation, contact pins operatively positioned in selected panels anddirectly engaging the selector contactor at a predetermined time, avariable tuning condenser for selecting the stations in a radioreceiver, and a plurality of selector bars controlled by current througheach pin when engaged by the selector contactor for checking themovement of the variable condenser to bring in the station correspondingto the pin so engaged.

5. In a station selector for radio receivers, a time piece with acontactor having constant speed, contacts arranged to be engagedserially' by the contactor, a selector contactor arranged for step bystep movement, a series of steps, an armature for holding and releasingthe contactor at each step, an electromagnet controlled by currentthrough the movable contactor and any of the said contacts for releasingthe releasable means to permit the selector contactor to move to thenext step, a switchboard containing a series of panels, one for eachstation, contact pins operatively positioned in selected panels andarranged to be engaged by the selector contactor at a predeterminedtime, a variable tuning condenser for selecting the stations in a radioreceiver, and a rotary drum whose movement is initiated by currentthrough each pin when engaged by the selector contactor for controllingthe position of the variable condenser to tune in the stationcorresponding to the pin so engaged.

6. In a station selector for radio receivers, a time piece with acontactor having constant speed, contacts arranged to be engagedserially by the contactor, a selector contactor arranged for step bystep movement, a series of steps, an armature for holding and releasingthe contactor at each step, an electromagnet controlled by currentthrough the movable contactor and any of the said contacts for releasingthe releasable means to permit the selector contactor to move to thenext step, a switchboard containing a series of panels, one for eachstation, contact pins operatively positioned in selected panels andarranged to be engaged by the selector contactor at a predeterminedtime, a variable tuning condenser for selecting the stations in a radioreceiver, and an electromagnetic clutch whose movement is initiated bycurrent through each pin when engaged by the selector contactor forcontrolling the movement of the variable condenser to tune in thestation corresponding to the pin so engaged.

'7. In a station selector for radio receivers, a time piece with acontactor having constant speed, contacts arranged to be engagedserially by the contactor, a selector contactor arranged for step bystep movement, a series of steps, an armature for holding and releasingthe contactor at each step, an electromagnet controlled by currentthrough the movable contactor and any of the said contacts for releasingthe releasable means to permit the selector contactor to move to thenext step, a switchboard containing a series of panels, one for eachstation, contact pins operatively positioned in selected panels anddirectly engaging the selector contactor at a predetermined time, avariable tuning condenser for selecting the stations in a radioreceiver, and a motor whose circuit is initially controlled by currentthrough each pin when engaged by the selector contactor for moving thevariable condenser to bring in the station corresponding to the pin soengaged.

8. In a station selector for radio receivers, a series of contacts, atime-controlled contact movable to engage the first contacts in apredetermined order, a carriage movable step by step under the controlof said contacts as they are progressively closed, a contactor carriedby the carriage, a panel corresponding to each station to be selected,contact pins removably carried by the panels and selectively arranged tobe engaged by the contactor at the proper times for receiving theselected stations, a rotary drum, means whereby a station is selectedaccording to the positions of the drum, and means whereby the closing ofany contact pin by the contactor stops the drum at the selectedposition.

9. In a station selector for radio receivers, a series of contacts, atime-controlled contact movable to engage the first contacts in apredetermined order, a carriage movable step by step under the controlof said contacts as they are progressively closed, a contactor carriedby the carriage, a panel corresponding to each station to be selected,contact pins removably carried by the panels and selectively arranged tobe engaged by the contactor at the proper times for receiving theselected stations, a rotary drum, radio tuning means attached to thedrum whereby a station is selected according to the position of thedrum, and selector bars, any of which may engage and stop the drum at aselected position when the contactor closes with any contact pin.

16. In a station selector for radio receivers, a series of contacts, atime-controlled contact movable to engage the first contacts in apredetermined order, a carriage movable step by step under the controlof said contacts as they are progressively closed, a contactor carriedby the carriage, a panel corresponding to each station to be selected,contact pins removably carried by the panels and selectively arranged tobe engaged by the contactor at the proper times for receiving theselected stations, a rotary drum, radio tuning means attached to thedrum whereby a station is selected according to the position of thedrum, selector bars, any of which may engage and stop the drum at theselected position by the closing of any contact pin by the contactor,and means whereby the operated selector bar may be reset to its normalposition after the drum is stopped in the selected tuned position.

11. In a station selector for radio receivers, a series of contacts, atime-controlled contact movable to engage the first contacts in apredetermined order, a carriage movable step by step under the controlof said contacts as they are progressively closed, a contactor carriedby the carriage, a panel corresponding to each station to be selected,contact pins removably carried by the panels and selectively arranged tobe engaged by the contactor at the proper times for receiving theselected stations, a rotary drum, radio tuning means attached to thedrum whereby a station is selected according to the position of thedrum, selector bars, any of which may engage and stop the drum at aselected position when the contactor closes with any contact pin, anelectromagnetically operated clutch, and a rotary cam operated throughthe clutch for resetting the selector bar to its normal position afterthe drum is stopped in the selected position.

12. In a station selector for radio receivers, a control circuit for thereceiver, a series of contacts, a time-controlled contact movable toengage the first contacts in a predetermined order, a carriage movablestep by step under the control of said contacts as they areprogressively closed, a contact carried by the carriage, a panelcorresponding to each station to be selected, contact pins removablycarried by the panels and selectively arranged to be engaged by thecontactor at the proper times for receiving the selected stations, arotary drum, radio tuning means attached to the drum whereby a stationis selected according to the position of the drum, selector bars, any ofwhich may engage and stop the drum at the selected position by theclosing of any contact pin by the contactor, a rotary cam for resettingthe selector bar to its normal position after the drum is stopped in theselected position, and means whereby the radio control circuit is openedwhen the movable contact engages one of the contacts.

13. In a station selector for radio receivers, a control circuit for thereceivers, a series of contacts, a time-controlled contact movable toengage the first contacts in a predetermined order, a carriage movablestep by step under the control of said contacts as they areprogressively closed, a contact carried by the carriage, a panelcorresponding to each station to be selected, contact pins removablycarried by the panels and selectively arranged to be engaged by thecontactor at the proper times for receiving the selected stations, arotary drum, radio tuning means attached to the drum whereby a stationis selected according to the position of the drum, selector bars, any ofwhich may engage and stop the drum at the selected position by theclosing of any contact pin by the contactor, a rotary cam for resettingthe selector bar to its normal position after the drum is stopped in theselected position, an electromagnetically operated switch for openingthe radio control circuit when the movable contact engages one of thecontacts, and means whereby the radio control circuit will beestablished only after the closing of any contact pin by the contactor.

DAVID L. GRUBB.

